Take a look at Thermalright GPU coolers. I think, since you got only (ONLY LOL) dual Xfire you can use their coolers and some low speed fans to cool the cards. Of course overall good case flow is key, the heat has to still leave the case. I was air on my 8800GT for a while, and TR did me good, temps were awesome. For you, it has to fit, but it will be quiet and your cards will thank you.
If the Wc for the CPu is good enuff, and you are only worried about the GPUs, then water is the key, you can put a rad of the back of the case. Again cost is a key. A loop will like I said, be $350, and another $100 for top notch, full cover blocks, quiet powrful rad, great pump, good res, quality fans, and quality hose. I spent $600+ to cool my CPU, 8800GT, and NB, and it's very quiet and powerful. I have UG to a 280GTX and a new $140 block to cool it, still cool and quiet. Not cheap.
Enuff blather. The RADIATOR in that system can only cool xxx watts of heat, no matter what pump or supersonic fans you can get. TT watercooling is a great noob start, but it's really limited. In short, the pump/rad/hose size etc is crap.
I have seen tags like this "Friends don't let friends buy Thermaltake WC".
If it cools the CPU to your needs then great, replace it when it breaks etc.
I'll steer you to some more technical links, please spend a few days (DAYS) reading posts, searching, learning.
Great place, not wayyy over the top with uber WC guys.
http://www.ocforums.com/index.php
Uber place, owned by one of the worls winning OC guys in the world. Not a place to post or ask questions by noobs, but an awesome place to learn.
http://www.xtremesystems.org/forums/
Another good place to learn
http://www.overclock.net/water-cooling/
The GURU of independant testing, worshipped by many.
http://www.martinsliquidlab.com/
Great places to buy WC stuff
http://www.dangerden.com/index.php?option=com_frontpage&Itemid=1
http://www.petrastechshop.com/
http://www.jab-tech.com/
Hope it helps, see ya in a few days, get edumacated!